SOUNDS THAT GIVE ONE THE "CREEPS"
We do hear a sound very like a groan. Even experienced mountain climbers can hardly keep down a "creepy" feeling when they hear it. This sound is made when the ice is cracking into a crevasse and while it is enlarging. These crevasses are formed by various strains in the ice as it moves along. So long as the strain which caused them continues the crevasses keep widening. The "groans" may be said to be "growing pains."
In some places you hear a constant roaring sound. The peasants are not superstitious about this sound however. They know it is made by what they call the "moulins" or mills of the glacier. Water, melting on the surface, makes streams. These, running together, make a larger stream. This stream, coming to a crack in the ice where a crevasse is just beginning, pours down, hollows out a little shaft and joins streams in the interior of the glacier, like that in which Agassiz took a bath when he didn't want to. The noise of the water, striking far below, comes up through the shaft, as a voice comes up through a speaking tube. But the crack into which the water falls must be very narrow, so that the water can melt both walls and thus form a shaft; otherwise it merely glides down the nearer wall and makes no sound.
NOISES WE PEBBLES HELP MAKE
Where two ice rivers emptying into a main stream come together you hear a constant dull rattle and rumble. This is made by the blocks of stone and trains of pebbles that have ridden in on the backs of the two glaciers thus going into partnership, falling between the glaciers at the point where they come together. The stones that do not fall over are brought together in the centre of the glacier and so make that spiny backbone of his, the "medial moraine." The rows of stones on the two sides of the glacier, called the "lateral moraines," have fallen piece by piece from the mountain walls as the glacier moved along between them.
But the strangest thing about the voices of the glaciers I have yet to tell. Whenever the sun is shining brightly, as I have said, and the gentians and the globe flowers open their petals and the birds start the chorus of the day, the glacier begins singing, too, humming to itself a pleasant tune. When the sky grows cloudy, even for a short time, the birds stop singing, the flowers cover their faces, the bees and butterflies hurry to shelter, and the glacier's song gradually dies away. Any cloud may bring rain, as far as the flowers and the bees and the butterflies know, and, for the same reason, the winged people hurry to cover because they don't want to get their wings wet. The flowers hide their faces to keep the rain from washing their pollen away, and the birds stop singing because, like the rest of us, they don't feel so cheerful under gloomy skies. But the glacier, why does he stop singing too? Because that murmuring tinkle you heard was made by the water melting on the glacier and running into rivulets a little way under its surface. When the sun stops shining the surface ice stops melting, the water gradually quits running and the murmur of the song dies away.
ON THE ROOF OF THE ANDES, WHERE IT'S TOO COLD TO GROW GLACIERS
It is because of these queer human habits of the glacier and, above all, his sensitive response to the moods of days and seasons, that many of the mountain people insist he is not only a living creature, but that he has a soul. We think of all this now as the western sun drops behind the snowy summits, the glacier's song grows silent, and we hear, mingling with the vespers of the birds, voices echoing from crag to crag the words of the psalm, "Praise ye the Lord." These are the voices, of the herdsmen speaking to each other from alp to alp—the evening call to prayer.
IV. How the Snow Men, the Glaciers, and the Rocks Go Walking